UV-Based Advanced Oxidation for NOM Degradation and Removal: Impacts on Characteristics, Biodegradability, and DBP Formation Potential

Transcription

1 UV-Based Advanced Oxidation for NOM Degradation and Removal: Impacts on Characteristics, Biodegradability, and DBP Formation Potential G.E. Imoberdorf, S. Sarathy, M. Bazri, & M. Mohseni Department of Chemical and Biological Engineering University of British Columbia Vancouver, Canada Friday July 29, 2011

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3 3 Acknowledgements RES EAU-WaterNET Strategic Network Natural Science and Engineering Research Council of Canada (NSERC) Trojan Technologies Alan Royce, Ted Mao, Mihalea Stefan

4 Water Treatment 4 UBC Degradation and removal of micropollutants and T&O from surface water UV-H2O2, Vacuum UV (VUV), UV photocatalysis Ozone Slow sand filtration Impact of advanced treatment processes on NOM Removal of NOM and improving raw water quality for downstream UV based AOP Ion exchange Electro-coagulation Solar disinfection (SODIS)

5 Water Treatment 5 UBC Degradation and removal of micropollutants and T&O from surface water UV-H2O2, Vacuum UV (VUV), UV photocatalysis Ozone Slow sand filtration Impact of advanced treatment processes on NOM Removal of NOM and improving raw water quality for downstream UV based AOP Ion exchange Electro-coagulation Solar disinfection (SODIS)

6 6 NOM Problems for advanced treatment processes Screening of UV Ozone consumption Membrane fouling Hydroxyl radical ( OH) scavenging

7 7 OH Reactions with NOM R H C H C C R R C H C H R R C C R

8 8 OH Reactions with NOM R O O H R O R R O

9 9 How does UV-based AOPs used for drinking water treatment affect water quality parameters?

10 10 AOPs Investigated H 2 O 2 /UV VUV H 2 O 2 /VUV

11 11 OH Generation UV, UV/H 2 O 2, VUV, and VUV/H 2 O 2 UV process no HO generation UV/H 2 O 2 process HO h 254 nm 2HO VUV process VUV/H 2 O 2 process HO 2 + h 185 nm HO H HO 2 + h 185 nm HO H HO h 254 nm 2HO HO + h 2HO nm

12 12 Comparison of Different AOPs (UV 254 fluence: 480 mj/cm 2 ) % Removal Geosmin 2,4-D Atrazine 0 VUV VUV/H2O2 UV/H2O2

13 13 Collimated Beam Experiments Operation variables Fluence: up to 2000 mj/cm 2 H 2 O 2 dose: up to 20 mg/l

14 14 Flow through Reactor Set-up Photoreactor VUV Hg lamp 185 nm 254 nm Storage tank Heat exchanger UV Hg lamp 254 nm Pump Air Control test

15 15 NOM Removal UV process TOC [mg L 1 ] Irradiation Time [min]

16 16 NOM Removal UV process TOC [mg L 1 ] UV/H 2 O 2 process Irradiation Time [min]

17 17 NOM Removal UV process TOC [mg L 1 ] VUV process UV/H 2 O 2 process Irradiation Time [min]

18 18 NOM Removal UV process TOC [mg L 1 ] VUV process UV/H 2 O 2 process VUV/H 2 O 2 process Irradiation Time [min]

19 DBP-FP (UV-H 2 O 2 treatment) mg/l H 2 O 2 Sarathy & Mohseni, Water Research (2010)

20 Chlorine Demand (UV-H 2 O 2 treatment) 20 Chlroine Demand (mg/l) Run 1 Run Fluence(mJ/cm²)

21 Aldehyde Formation (UV-H2O2 treatment) 21 Sarathy & Mohseni, Canadian J. Civil Eng., 36: (2009)

22 Aldehyde Formation (UV-H2O2 treatment) 22 Sarathy & Mohseni, Canadian J. Civil Eng., 36: (2009)

23 Aldehyde Formation (UV-H2O2 treatment) 23 Sarathy & Mohseni, Canadian J. Civil Eng., 36: (2009)

24 Aldehyde Formation (UV-H2O2 treatment) 24 Sarathy & Mohseni, Canadian J. Civil Eng., 36: (2009)

25 Aldehyde Formation (VUV treatment) Formaldehyde (C1) Suwannee water Aldehydes (ppb) Propanal (C3) Aceltaldehyde (C2) 20 Butanal (C4) Irradiation Time (min)

26 Aldehyde Formation (VUV treatment) Aldehydes (ppb) C1 C3 C2 C Irradiation Time (min) VUV process

27 Aldehyde Formation (VUV treatment) Aldehydes (ppb) C1 C3 C C Irradiation Time (min) Irradiation Time (min) VUV process VUV-H 2 O 2 process

28 Aldehyde Formation (UV-H 2 O 2 treatment Effect of Alkalinity) 28

29 AMW Distribution (UV-H 2 O 2 treatment) 29 Sarathy & Mohseni, ES&T, 2007

30 AMW Distribution (UV-H 2 O 2 treatment) 30 Sarathy & Mohseni, ES&T, 2007

31 AMW Distribution (UV-H 2 O 2 treatment) 31 Sarathy & Mohseni, ES&T, 2007

32 AMW Distribution (VUV & VUV-H 2 O 2 treatments) Abs 260 (cm -1 ) t = 0 t = 10 min t = 20 min t = 30 min t = 40 min t = 50 min t = 60 min Abs 260 (cm -1 ) t = 0 t = 10 min t = 20 min t = 30 min t = 40 min t = 50 min t = 60 min Retention time (min) Retention time (min) VUV process H 2 O 2 /VUV process

33 Biodegradability Increase (UV-H 2 O 2 treatment) BI Water BDOC ( g/l) Capilano Water Raw UV Fluence (mj/cm 2 )

34 Biodegradability Increase (UV-H 2 O 2 treatment) 34

35 35 Summary UV-based AOPs partially oxidize and change the composition and characteristics of NOM OH radical preferentially reacts with high to medium molecular weight organics Leading to the formation of low MW species UV-based AOPs lead to increases in biodegradability of NOM BDOC (or AOC) formation is proportional to the amount of TOC in water

36 36 AOP + BAC [FA] (ppb) % 85.5% 71.8% 82.9% 80.2% 82.4% Duration (days) Sarathy et al., 2011

37 37 AOP + BAC BDOC (%) Water Blank AOP AOP-BAC BAC

38 Thank You! Madjid Mohseni University of British Columbia Vancouver, BC